Bucket for elastic-fluid turbines.



U. PfSTEINMETZ. BUCKET 'Fon BLASTIG FLUID TUBBINES.

` nrmonxon nun nov. e, 1901. 24,852. Patented June 15,1909. n Sanus-slum 1.

Inventor:

G. P. STEINMETZ. BUCKET PQR ELASTIG FLUID TURBINBS.

APPLICATION FILED NOV. 6, 1907.

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UNITED STATES `'PATENT ormoni.

CHARLES P. STEINMETZ, 4OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, AOORPORATION OF NEW YORK.

BUCKET FOR ELASTIC-FLUID TURBINI'ES.

Specicationof Letters Patent.

Patented June 16, 190e.

To all whom it may concern: I Be 1t known that LCHARLES P..STE1N METZ, a citizen of the United States, residing at Schenectady, county of Schenectady,

' State of New York, have invented certain new and useful Improvements in Buckets for g Elast1c-Flu1d Turbines, of which the following is a-specification.

Inyestigations show that `in an impact elastic Huid turbine as the fluid flows through the Working passages and acts on the bucket faces, a loss occurs which decreases the effiof the machine. This loss is due princiencly y to the'turning of the fluid stream 'by cipal i the curved face of the bucket, and to the' shock due to the impact of the fluid particles on said face. My invention has for its object to improvev the shape of the working face of the buckets uns mmetric -u'ga force of the Huid stream on the entrance 'and thereby eliminate or largely reduce the loss mentioned above. To reduce this loss to a mimmum my improved buckets are provided with an entrance ortion that is very much less curved than tfie exit portion, and

.the shock or impact angle is made as small as possible consistent with the eective ex traction of energy from the motive fluid.

In one of the forms illustrative of the invention the working face of the bucket is composed of circular portions struck from. different radii, the said bucket being unsym-L ,metn'cal and having different entrance .and exit angles.- In a second form the working lface is composed of circular portions joined by a straight ortion, the bucket also being all). In these forms thecentrif- In a-third andi-preferred form of my inven-l tion the working face of the bucket is'com- .posed of spirallycurved 1Eportions so that the centrifug force of .the uid stream is rad- -ually increased'from zeroor a small nite V-va ue to a maximum anddecreased again to4 zere or to a small finite value at the pint of discharge. The bucket is also unsyminetrical.

Since the release of the fluid stream or et from centrifugal acceleration can take place without injurious effects much more rapidly than its application, I so arrange the buckets that the `discharge orexitside is shorter than the inlet. In the referred form of my invention the point o maximum curvature will be fairly near the exit, and the-initial part of the centrifugal acceleration will increase at a much slower rate* than the centrifugal deceleration. To produce a small im act angle, the entrance portion of each buc *et from the entrance to the point of maximum 'curvature may consist of two spiral parts joining each other and such that the second, or middle portion of-the bucket, gives a greater rate acceleration, thanv the first or entrance portion.

In the accompanying drawing, showing buckets illustrative of my invention, Figure l is an end View of a bucket having' a small shock of impact angle whose Walls are composed of circular portions of different curva-v ture; Fig. 2 is an end view of asimilar bucket having curved lportions united by straight portions, and Fig. 3 is an end view ofmy preferred form of bucket composed of spiral parts having different rates of increase of. curvature.

Referring to Fig. 11 indicates a compound bucket which may be integral With or ,separate from yits support as desired. When separate, any good mechanical means may be employed to unite the buckets' lwith their support. ,The working face of each bucket is composed of two .circular portions 2 and 3, the radius ,by which the portion 2 is struck being considerably longer than that einvloycd for portion 3. The rear faces of the shorter radii. The ci-oss-sectional area of the bucket spaces or working passage should be great enough to carry the motive fluid Without choking on the one hand or permitting it to unduly expanden the other. The angle of entrance of the buckets in this particular embodiment is 3V and the angle of discharge 270. The line 4 is tangential to the rear face 5 of the bucket and indicates cles in the jet. The line 6 is tangential to the curve of the working face of the bucket at the point of intersection with tlic line 4 and the angle between these two lines is SSO which is of increase of curvature and so of centrifugal uckets-are similarly shaped but made with the direction of movement of the steam partiv the shock or impact angle. Owing to the lic peculiar curvature of the bucket face this angle isvery much smaller than would be possible fora given nozzle angle and a bucket With a circular face, meaning by circular face a bucket whose face forms a part of a true c linder.

In' ig. 2 is shown another form of compound bucket wherein the curved portions 2 and 3l of the bucket are joined by a straight ortion 7, the rear Wall of the bucket followmg the same arrangement. In this case, the angle of impact is 30, which is less than 1n the first illustration.

In Fig. 1 as the steam enters the bucket its centrifugal force immediately rises to a moderate value and later rises to a maximum value which is maintained until the' steam is discharged. f

In Fig. 2 as thesteam enters the bucket its centrifugal force immediately rises to a moderate value, then decreases to zero as it reaches the straight portion and finally rises to the maximum which is maintained until the steam is discharged. In both of theseV cases, however, the centrifugal force of the steam in the inlet portion ofthe bucket is less than it.would be in the case of avcircular bucket, and the shock angle is ver much smaller. Hence a turbine fitted witlvi either of these two forms has the advantages accruing from moderate initial centrifugal comp'ssion of the steam and a small shock ang e.

In Fig. 3 is shown the preferred form of my invention wherein the Working face of the bucket is composed of three curved portions 2, 3 and S.' In this embodiment the 'length of the curved or inlet portion 2 greatly exceeds the length of the curved or discharge portion S. rThe angle of impact is small, be ing 30, so that I gain all of the advantages resulting therefrom. As the steam passes oyer the port-ion 2 to the point of impact, the rate of increase of the centrifugal force is small. From this point to that of maximum curvature, the rate of increase of centrifugal force is larger F rom the point of maximum curvature to the exit the rate of decrease of centrifugal force is large.

The portions or sections 2 and 3 are made up ol' two dill'eruent spiral curves having different rates of increase of curvature. .It will be noted that the bucket is unsynimetrical with the inlet portion much longer than the discharge portion. "his means'that-the increase and' decrease ol' the centrifugal force of' the steam takes place gradually, but the rato ol iiu:.rease is less than the rate of decrease or release.

ln accordance with the provisions of' the patent statutes, l' have described the principle of operation of my invention, together with the apparatus which l now consider to represent the best. embodiment thereof but I desire to have it understood that the apparatus shown is only illustrative, and that the inf l vention can be carried out by other means.

What I claim as new, and desire to sc cure by Letters Patent of the United States, 1s,-

having a working face composed of entrance and exit portions of varying curvature, one of said portions being less curved than another to produce a variation in the cent-rifu 2. A bucket' for an elast-ic fluid turbine having .a Working face composed of entrance curvature, the entrance portion being less .curved and the rate of its change of curvature also being less than that of the exit poron the entrance than on the exit portion.

3. A bucket for an elastic fluid turbine, having a working face composed 0f two or more portions of dissimilarand varying curvature to reduce a gradual variation in the centrifuga force of the fluid stream as it flows over said face.

4. A bucket vfor an elastic fluid turbine having a working face which is`s'o `sha ed that the centrifugal force of the motive uid is less on the entrance than on the discharge side, said force gradually increasing from zero or a small finite'value at the inlet to a maximum value and4 then gradually decreasing to zero or asmall finite value at the outlet. 1

5. A bucket for an elastic `fluid turbine, having a working face one portion of which is shaped to gradually increase the centrifugal force of the jet to the maximum and has an angle of impact which is less than that of a cylindrical surface with the same entrance angle, the discharge portion being shaped t0 gradually release the jet of its centrifugal force at agi-eater rate than it was acquired.

6. A bucket for an elastic fluid turbine having a working l'ace comprising inlet and outlet portions, the' inlet portion bein curved to gradually increase the centrifuga force of the jet and the discharge portieri` being curved to gradually decrease the centrifugal force of the jet, the said inlet portion being longer than the outlet.

7. A bucket for an elastic fluid turbine having a working face comprising inlet and outlet portions, the inlet portion forming a part ol' a spiral curve which gradually increases the centrifugal force of' the jet, the discharge portion also forming a part of a spiral curve which releases the jet of said force at a greater rate than it Was acquired.

S. An uusymlnetrical bucket for an elastic lluid turbine having a curved Working face, the entrance angle ol' which is greater than the discharge angle, the said Yface being co1nt posed of' two portions forming reversed spiral curves, .one of said curves being longer than the other.

1. A bucket for an elastic ,fluid turbine,

gal force of the fluid jet as it flows over it.

and exit portions of different and varyingr tion, so that the centrifugal force will be less` 9. An unsymmetrical bucket for elastic fluid turbines, having a curved Working face whose entrance angle is greater than the discharge angle and is composed of two portions 5 forming reversed spiral curves, the inlet portion being longer than `the outlet and shaped to gradually increase the centrifugal force of the fluid jet to the maximum, the outlet portion being shaped to release'the jet of its centrifugal force at a greater rate than it was acquired. n

10. An unsymmetrical bucket for elastic fluid turbines having a curved Working face,

. th'e inlet portion of which has a va ing curia vature which causes the centrifuga force to increase at a given rate for a certain distance along said face and then causes it to increase at agreater rate to a maximum at the beginning of the discharge portion, said discharge portion having a varying curvature which decreases the centrifugal force at a greater rate than it was increased by the inletI portion.A

1I. A11 unsyrnmetrical bucket for elastic fluid turbines-.having-a curved working face,

the inlet portion of is longer vthan the .discharge portion and is formed on spiral -of the discharge portionF said discharge or' tion being for e on aspiral curve w osg# curvature rad a yf decreases at a greate\ rate than t e curvature of the inlet portion 35 increases.

12. A bucket for an elastic fluid turbine having a- Working faceuformed of three portions of different curvature".

13. A bucket for an elastic fluid turbine 40 having a working face formed of three spiral curves having d1iferent rates of increase of curvature. 2 gh l In witness whereof, I have ereunto set my hand this 5th day of N ove'mber,'1907 45 CHARLES P. STEINMETAZ. j

ace, and then increases gradually ata Y 

